Function read_word 

fn read_word(s: &str) -> Result<Option<(&str, &str)>, BrokenQuote>

Read the next word in a OpenWRT config line. Strip any surrounding quotation marks.

Returns

• a tuple Some((word, remaining_line)) if found,
• None if the line is exhausted, or
• Err(BrokenQuote) if the line could not be parsed.